Reaction of hydrogen bromide with diols of long chain α,β-unsaturated acids

The reaction oferythro- andthreo-glycols oftrans-2-hexadecenoic andtrans-2-docosenoic acids with hydrogen bromide in the presence of acetic anhydride has been investigated. In each case,erythro-2,3-dihydroxy acid gave a separable mixture of isomericthreo-2(3)-bromo-3(2)-acetoxy acids. In contrast,threo-2,3-dihydroxy acid yielded only one isomericerythro-2-bromo-3-acetoxy acid. The structures of individual bromo-acetoxy acids have been established by chemical as well as spectral studies. Stereoselectivity observed in the reaction of hydrogen bromide withthreo-glycol has been explained on the basis of different conformations of the diastereoisomeric 2,3-glycols.     

Composition of novel triesters from the skin of the rhino mutant mouse

Composition of two novel triesters, derived from the skin of the rhino mutant mouse, is described. Chemical and spectroscopic analysis of the products of pancreatic hydrolysis of the triesters showed that these are comprised predominantly of isomer I (92.7 mole %). The syntheses of two reference compounds, 1-O-hexadecanoyl-2-[(14-hexadecanoyloxy)O-tetradecanoyl] 1,2-hexadecanediol (Ia) and 2-O-hexadecanoyl-1-[(14-hexadecanoyloxy)O-tetradecanoyl]-1,2-hexadecanediol (IIa), corresponding in their structures to isomers I and II of the triester, wax have also been described. Presented at the AOCS 49th Annual Fall Meeting, Cincinnati, Sept. 1975.     

一锅法合成4-溴丁基乙酸酯

以1,4-丁二醇、氢溴酸(48%)和冰醋酸为原料,在带水剂的作用下一锅法合成了4-溴丁基乙酸酯。考察了带水剂类型及追加冰醋酸或醋酸酐量对产率的影响,并通过气质联用对粗产品进行了分析测定,推断其反应机理。结果表明,较适宜的合成条件为1,4-丁二醇0.21 mol,1,4-丁二醇∶氢溴酸(48%)∶醋酸摩尔比为1∶1∶1.3,在带水剂甲苯(21 mL)的作用下,反应2.5 h,反应结束前1 h追加0.01 mol醋酸酐,合成效果最好,产率可达到91.2%,反应主要副产1,4-二溴丁烷、4-溴-1-丁醇、四氢呋喃和1,4-丁二醇二乙酸酯。     

糠醛合成1,2-二乙酰氧基-1,2-双(2-呋喃基)乙烯的新工艺

以糠醛为原料 ,VB1 为催化剂 ,利用偶姻缩合合成了糠偶姻 ,并以此为原料 ,改变以往先溶解后降温 ,然后在低温下反应的传统工艺 ,使其醋酸酐化得到 1,2 二乙酰氧基 1,2 双 ( 2 呋喃基 )乙烯。讨论了反应温度、反应时间、催化剂用量以及投料比等因素对产物收率的影响 ,确定最佳合成工艺条件为 :反应温度 130～ 140℃ ,反应时间 3h ,催化剂、糠偶姻与醋酸酐的物质的量比为 0 0 2 88∶0 0 15 6∶0 0 85 3。产物的收率提高到 86 1% ,其熔点为 2 0 2～ 2 0 4℃。通过元素分析、GC -Mass谱、IR谱、1 HNMR谱对所合成的化合物进行了全面分析表征 ,证实了其分子结构式     

Properties and reactivity of Fe-MCM-41 catalysts prepared by microwave irradiation method for acetylation of 1, 2-dimethoxybenzene

The liquid phase of acetylation of 1,2-dimethoxybenzene with acetic anhydride has been investigated over a series of acid iron-mesoporous materials (Fe-MCM-41) synthesized by microwave irradiation method with different Si/Fe ratios (Si/Fe?=?80, 50, 10) and characterized by several spectroscopic techniques such as: N₂ physical adsorption, ICP, XRD, TEM, FT-IR, and a temperature?Cprogrammed?Cdesorption (TPD) of pyridine. In fact, the catalyst Fe-MCM-41 (10) showed bigger performance in the acid-catalyzed acetylation of 1,2-dimethoxybenzene employing acetic anhydride as an acylating agent. Furthermore, the kinetics of the acetylation of 1,2-dimethoxybenzene over these catalysts have also been investigated.     

3-氯-1,2-丙二醇及缩水甘油的合成研究

以甘油为原料,在无水乙酸的作用下与HCl反应合成出3-氯-1,2-丙二醇,优化了3-氯-1,2-丙二醇的合成工艺,得到适宜的反应条件为:反应温度90℃,反应时间4 h,催化剂用量5%(w/w),HCl气体流速20 L/h。然后利用制备的3-氯-1,2-丙二醇在二氯甲烷溶剂中与强碱性阴离子交换树脂作用合成了缩水甘油,最佳反应时间为1 h。产物分别通过GC和IR进行了鉴定,3-氯-1,2-丙二醇和缩水甘油的产率分别可达到84.6%和89.6%。     

外源抗氧化剂7-(4-氨基-1,2,4-三唑-5-)硫乙氧基黄酮及其意外乙酰化产物的合成

7-溴乙氧基黄酮与3-取代-4-氨基-1,2,4-三唑-5-硫醇类化合物缩合反应得到7-(4-氨基-1,2,4-三唑-5-)硫乙氧基黄酮,为了增加其脂溶性,将该类化合物进一步与乙酸酐回流反应12 h,得到的化合物不是预期的7-(3-取代-4-乙酰氨基-1,2,4-三唑-5-)硫乙氧基黄酮衍生物,而是7-[3-取代-4-(2-乙酰氧基)-乙亚氨基-1,2,4-三唑-5-]硫乙氧基黄酮,分别用红外、核磁共振氢谱及碳谱、质谱和元素分析对这4个乙酰化产物的结构进行了确证。以清除超氧自由基、羟自由基、亚硝基自由基和2,2-二苯基-1-苦味酰基自由基的活性及总还原能力为指标,测定比较了4个7-(3-取代-4-氨基-1,2,4-三唑-5-)硫乙氧基黄酮化合物及其意外乙酰化产物的体外抗氧化活性。结果表明,在测定浓度下,乙酰化衍生物7-[3-对甲氧苯基-4-(2-乙酰氧基)-乙亚氨基-1,2,4-三唑-5-]硫乙氧基黄酮较其前体抗氧化活性强。     

4-硝基苯乙基溴合成

以β-溴苯乙烷为原料,以醋酸、醋酐和发烟硝酸为硝化剂合成4-硝基苯乙基溴。实验考察了反应条件对产品收率的影响。实验表明适宜的反应条件是：反应温度控制在-5℃,0．1mol β-溴苯乙烷需要0．15mol的发烟硝酸和0．12mol醋酐,反应时间为4小时,4-硝基苯乙基溴收率达69．2％。     

4-硝基苯乙基溴的合成

以β-溴苯乙烷为原料,以醋酸、醋酐和发烟硝酸为硝化剂合成4-硝基苯乙基溴。实验考察了反应条件对产品收率的影响。实验表明适宜的反应条件是：反应温度控制在-5℃,0．1molβ-溴苯乙烷需要0．15mol的发烟硝酸和0．12mol醋酐,反应时间为4小时,4-硝基苯乙基溴收率达69．2％。     

2-脱氧-D-葡萄糖的合成

以无水葡萄糖为原料,通过乙酸酐保护、HBr溴代、锌粉还原、脱保护和酸水解5步反应合成了2-脱氧-D-葡萄糖,总收率为30%,其结构经过核磁共振谱图分析验证。该合成新方法与传统方法相比,避免了催化加氢步骤,缩短了总反应时间,提高了总产率,减少生产成本,简化工艺操作,适宜工业化规模生产。     

玫红酸三乙酸酯的合成

以玫红酸、醋酸酐为原料,采用加热回流法合成了玫红酸三乙酸酯[三(4-乙酰氧基)苯基甲烷].通过紫外、红外、1HNMR等方法定性分析产物.考察了反应时间、溶剂配比和反应物配比对产率的影响,在最佳反应条件下,玫红酸三乙酸酯的产率达54.6%.     

三醋酸甘油酯绿色合成工艺

用甘油与醋酸、醋酐或醋酸与醋酐混合物作反应物,以五水四氯化锡(SnCl4.5H2O)和磷钨酸(H3O40-PW1.2xH2O)作催化剂,合成三醋酸甘油酯。研究了不同工艺条件对反应产率的影响。结果证明,用醋酐或醋酐加醋酸混合物优于仅用醋酸,适宜的物料比为:甘油∶醋酸∶醋酐=1∶2∶1(摩尔比)。用SnCl4.5H2O催化,优于杂多酸。以甲苯作带水剂适宜的反应温度为105~120℃,脱溶温度为120~140℃,产率达85%~90%。反应与精馏单釜完成。工艺简单,污染少。     

5-取代-1-乙酰基-2-硫代海因衍生物的微波快速合成

微波辐射下,硫氰酸铵与a-氨基酸在乙酸酐和冰乙酸的混合溶剂中反应,快速合成了9种5-取代-1-乙酰基-2-硫代海因衍生物. 探讨了微波反应时间、微波反应温度、硫氰酸铵用量及乙酸酐用量对产率的影响,得到了最佳反应条件：a-氨基酸用量10 mmol,硫氰酸铵用量16 mmol,乙酸酐用量9 mL(冰乙酸用量1 mL),微波反应温度100℃,微波反应时间2 min. 与常规加热法相比,反应时间由30 min缩短到2 min,产率由55.2%~79.5%提高到85.0%~93.0%. 产物结构经1H-NMR, IR和元素分析验证.     

Action of Hydrogen Bromide on Threo- and Erythro-13,14-Dihydroxybehenic Acids and the Stereochemistry of Their Mutual Transformations

Threo- and erythro-13,14-dihydroxybehenic acids on treatment with hydrogen bromide in acetic anhydride yielded the erythro- and threo-13(14)-bromo-14(13)-acetoxybehenic acids respectively. In addition, an abnormal reaction product has been isolated and characterised as 13(14)-ketobehenic acids. The studies on the stereochemical relationships, involved in the transformation of cis- and trans-13-docosenoic acids to their corresponding dihydroxy acids through the intermediate bromoacetoxy and epoxy acids, have led to the conclusions that support Swern's reaction scheme of the unsaturated fatty acids.     

Hydrogen bromide titration for soaps in fat products

Since none of the existing methods for determining soaps in fat products have been found to be entirely satisfactory, a method has been devised for the determination of alkali metal soaps by direct titration with Durbetaki reagent (hydrogen bromide dissolved in glacial acetic acid). When the titration was conducted at room temperature in acetic acid-benzene solution with crystal violet as indicator, soaps of potassium, sodium and lithium could be determined accurately in anhydrous oils, monoglycerides, and sucrose esters. The presence of alcohols, glycerol and sucrose did not interfere in the direct titration. However, oxidized oils, epoxides, and cyclopropenoid acids, which are known to consume hydrogen bromide, did interfere. Products containing the interfering substances could be analyzed by a modified procedure in which the alkali metal cations were extracted from a mixture of amyl acetate andn-butanol (1:3) into an aqueous solution of acetic acid, and titrated as the acetates.     

酸性中心对复合氧化物催化苯酚羟基化反应的影响

铁基复合氧化物催化苯酚羟基化反应具有明显的诱导期,适当引入酸性中心,在氧化还原活性位的共同存在下,可以迅速缩短羟基化反应的诱导期;酸性中心弱或没有采用酸改性的复合氧化物催化剂,对苯酚羟基化反应催化作用活性低,催化剂用量大,反应诱导期不稳定。乙酸、乙酸酐等有机弱酸可以直接加入羟基化反应体系。对复合氧化物催化剂进行后处理改性,引入适当的酸性中心,有助于提高催化剂的活性,缩短甚至消除羟基化反应诱导期,避免由于未反应过氧化氢的积累增加反应器运行的风险,提高过氧化氢有效利用率和目标产物选择性。将5.3g苯酚、0.051g催化剂、过氧化氢与苯酚的物质的量比为0.33,在65℃下,于10.6g溶剂水中反应,时间为30min,反应诱导期仅5min,苯酚转化率达21.2%,苯二酚选择性为92.9%,过氧化氢有效利用率为59.6%。分析了直接加入酸性中心和对复合氧化物催化剂进行酸改性所带来的问题,推测了苯酚羟基化反应的机理。     

高浓度过氧乙酸的实验室制备方法

提出了一种实验室条件下简便、安全制备高浓度过氧乙酸的方法.先把低质量分数的双氧水浓缩到78％左右.然后比较了用乙酸和乙酸酐分别与过氧化氢反应制备所得的过氧乙酸的质量分数.采用乙酸酐(97％)/过氧化氢反应,当过氧化氢质量分数为78.5％时,在40℃下反应4h,室温放置2h,制得过氧乙酸质量分数为48.2％.     

4,5-二甲基-1,2-二苯胺的合成工艺改进

以3,4-二甲基苯胺为原料,合成了4,5-二甲基-1,2-二苯胺,产品收率达69%以上。在乙酰化、硝化反应中引入了1,2-二氯乙烷溶剂。用正交实验确定了最佳原料配比:n(3,4-二甲基苯胺)∶n(醋酸酐)∶n(硫酸)=1.00∶1.15∶1.10,硝化反应温度为13°C,反应时间为3.5h,硝化产物收率为90.56%,溶剂回收率95%以上。改进后,每摩尔母体的醋酸酐用量由303g减少至118g,浓硫酸用量由304g减少至108g。     

Studies in potential antifertility agents: part 20: Synthesis of tetraphenylethane basis ethers & 1, 2-Bis (4'-hydroxyphenyl)-1,2-diphenylethylene

Tetraphenylethane basic ethers have been synthesized and screened for their antifertility activity. Some of them showed significant activity. 2-(4'beta Diethylaminoethoxyphenyl)-l,1-diphenylethane appears to be the most active as it prevents implantation in rates at 3.5 mg/kg. The stucture relationship activity in the series are discussed. The unreacted methyl ether (2.5 g) was recovered from the benzene layer. 1,2-Bis (4'-acetoxyphenyl)-1,2-diphenylethylene--1,2-Bis (4'-hydroxyphenyl)-1,2-diphenylethylene (1-2g) was dissolved in acetic anhydride (6 ml) and dry pyridine (0.5) added. After 24 hours the reaction mixture was poured over crushed ice and the white product that separated was filtered and crystallized from ethanol; m.p. 163 degrees; NMR (CDC13); 2.98(m, 18H, Ar-H), 7.79 (s, 6H, -0-COCH3) (Fourd: C, 79.99; H, 5.70. C30H2404 requires C, 80.36; H, 5.36%).     

1,3-二乙酰氧基-2-乙酰氧基甲氧基丙烷的合成

以环氧氯丙烷为起始原料与浓盐酸反应制得1,3-二氯-2-丙醇,再在浓硫酸催化下与多聚甲醛缩合得1,3-二氯-2-丙醇的半缩甲醛,不经分离,直接用醋酐酰化得1,3-二氯-2-乙酰氧基甲氧基丙烷,后者与醋酸钠反应得标题化合物。以环氧氯丙烷计4步反应总收率为55.6%。